A flicker filter is adjusted according to degree of alpha blending performed on a display signal. For some weakly showing graphics images, a lower flicker filter level may be implemented or the flicker filter may be turned off. A threshold for turning off the flicker filter may be programmable. Other embodiments are described and claimed.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method comprising: receiving an alpha value indicative of how a video signal and a graphics signal are to be combined; comparing the alpha value to a threshold value; obtaining a result of the comparison; subtracting the threshold value from the alpha value to arrive at a second result; and turning off a flicker filter if the alpha value is below the threshold value, and otherwise adjusting, based at least in part on the second result, a filter level of the flicker filter if the alpha value exceeds the threshold value.
2. The method of claim 1 , further comprising adjusting the filter level of the flicker filter responsive to the result.
3. The method of claim 1 , further comprising: dividing the second result by an alpha step value to arrive at a third result; and adjusting the filter level of the flicker filter based on the third result.
4. The method of claim 1 , further comprising turning off the flicker filter if the graphics signal to be displayed with the video signal is substantially transparent.
5. The method of claim 1 , further comprising evaluating the graphics signal to produce the threshold value.
6. A system comprising: a processor to execute instructions; a controller coupled to the processor to compare an alpha value indicative of how a video signal and a graphics signal are to be combined to a threshold value to arrive at a result, and control a filter level of a flicker filter based on the result, wherein the control is further based on subtraction of the threshold value from the alpha value to arrive at a second result, division of the second result by an alpha step value to arrive at a third result, and adjustment of the filter level of the flicker filter based on the third result, wherein the alpha step value is a number of alpha value increments in a mid-range of alpha values at which the filter level is to change; and a dynamic random access memory (DRAM) coupled to the controller.
7. The system of claim 6 , wherein the controller is to turn off the flicker filter if the threshold value exceeds the alpha value.
8. The system of claim 6 , wherein the system comprises a set-top box.
9. The system of claim 6 , wherein the system is to receive a radio frequency (RF) signal including video information and to obtain the video signal from the RF signal.
10. The system of claim 9 , wherein the controller is to mix the video signal with the graphics signal, wherein the controller is to generate the graphics signal.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 23, 2006
August 16, 2011
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